Laparoscopic surgical procedures have been around for many years and have recently have become more available due to advances in technology relating to the laparoscope or video imaging system. They are much less intrusive to the patient than typical open surgical procedures. While an open surgical procedure may involve one primary incision that is at least 6-9 centimeters long, a laparoscopic procedure typically uses smaller incisions, each only around 5-11 millimeters in length. In open surgery, the surgeon cuts muscle. In laparoscopic surgery, the surgeon generally does not cut muscle. Because they are less intrusive than open surgical procedures, laparoscopic procedures have resulted in much shorter surgical procedures and recovery times.
Laparoscopic procedures have typically involved insufflation of the abdominal or peritoneal cavity with carbon dioxide and/or other gases in order to create a pneumoperitoneum. The pneumoperitoneum establishes an open space inside the peritoneal cavity to enable the surgeon to move the laparoscope around and see inside.
Typically, the pneumoperitoneum is established by puncturing the abdominal wall with a Veress needle and injecting gas from an insufflator through the Veress needle to a pressure of around 12 mm Hg.
After insufflation, a trocar is advanced through the opening in the abdominal wall and into the peritoneal cavity. The trocar is a tube or cannula that usually has a gaseous seal to contain the carbon dioxide within the peritoneal cavity and maintain insufflation. The cannula is used for insertion of other medical instruments, such as a laparoscope, therethrough and into the peritoneal cavity.
There may be difficulties associated with insufflation of the peritoneal cavity. First and foremost is postoperative pain which patients may experience in the abdomen or shoulder area due to migrating gas. This occurs when insufflation causes excess gas pressure in the peritoneal cavity. Excess gas pressure may also compress the pleural cavities thus making respiration difficult. Other possible difficulties associated with insufflation in laparoscopic surgery include subcutaneous emphysema, blood vessel penetration, etc.
The attendant difficulties of insufflation have led to alternatives to insufflation wherein a pneumoperitoneum is established by elevating the abdominal wall with a mechanical lift. The lift is introduced percutaneously into the peritoneal cavity before establishing a pneumoperitoneum. The lift is elevated mechanically in order to distend the abdomen. When the abdomen is distended, ambient air enters the peritoneum through the puncture opening in the abdomen and a pneumoperitoneum at or near ambient air pressure is established.
By establishing a pneumoperitoneum at ambient air pressure, insufflation and the concomitant need for gaseous seals in endoscopic instruments and trocars for maintaining a relatively high gas pressure in the peritoneal cavity is eliminated. Thus, the attendant difficulties of insufflation, as well as the need for costly equipment, is eliminated.
The prior art includes several abdominal lift devices. In International Patent Application PCT/US92/4456 a lift is disclosed that has two radially extending blades that are rotatable. The blades are closed together for initial insertion into the abdominal cavity. After insertion, the blades are spread or fanned. When the lift is elevated, the blades contact and elevate the inner surface of the abdominal wall.
Societe 3X, a French company, markets an abdominal lift and support structure. The lift is shown and described in International Patent Application Serial No. PCT/FR91/227. The lift includes a series of curves forming a generally triangular shape. The tip of the lift is turned downwardly slightly. The support structure includes a crane and boom design. Gross adjustments are made by sliding the supporting legs and the boom within their respective holders. A mechanical screw-jack is used for fine adjustment.
U.S. Pat. No. 5,183,033 describes a method for lifting an abdominal wall with a set of linear and non-linear abdominal lifts. International Patent Application PCT/U.S. No. 92/4392 describes a variety of mechanical rods, arms and/or balloons for mechanically lifting an abdominal wall during laparoscopic surgery.
There are some other prior art structures for elevating and/or supporting abdominal lifts in laparoscopic surgery. U.S. Pat. No. 5,183,033 illustrates support structures using winches or U-shaped bars for use in laparoscopic surgery.
Further, there are a number of prior art support structures for supporting mechanical lifts used in open surgery. For example, see U.S. Pat. Nos. 5,109,831 and 4,143,652.
The adjustment capabilities of these prior art devices are limited. It would be desirable to provide a support structure for holding an abdominal lift in an elevated position that is mechanically operable by the surgeon at the operating room table and has a variety of position adjustments. It would be desirable to provide a mechanical lift adjustment having both gross and fine adjustment capabilities and can be adjusted for left or right-handed operation. Also, it would be desirable to provide a latch mechanism associated with the lift mechanism wherein a leg assembly of the support structure automatically engages a base in order to fix the height of the abdominal lift.